An
outbreak of yellow vein disease of aster (Kalimeris
indica,family Asteraceae) was observed at Lucknow, India in the winters of 2010
and 2011. During a survey in winter 2012, 23% (56/234) of aster plants exhibited yellow vein
disease symptoms at NBRI gardens in Lucknow and a higher disease incidence of 34% (125/367) was found
in other gardens at Lucknow. All 181 infected
plants exhibited highly similar yellow vein symptoms (Fig. 1) as compared to healthy ones. Presence of whiteflies
in the vicinity and the typical yellow
vein symptoms suggested a begomovirus infection. For diagnosis, total DNA was
extracted from samples of five plants showing symptoms (collected from two
locations) and from one symptomless plant. PCR was then performed using PALIc1960/PALIv722 begomovirus
specific primer pair (Rojas et al.,
1993) and beta-01/beta-02 beta satellite specific primer pair (Briddon et al., 2003). By contrast to the DNA sample of the symptomless aster
plant, all the five samples from diseased plants showed PCR products of
expected sizes for a begomovirus (~1.2 kb; Fig. 2a) and a beta satellite (~1.3
kb; Fig. 2b), which indicates their association with
the disease.

For
identification of the begomovirus, Φ-29 DNA polymerase-based rolling circle amplification
(RCA)(TempliPhi kit, GE healthcare, USA) was performed
followed by restriction digestions with BamHI enzyme. A representative DNA sample of an infected aster was used
as a template. The resulting fragment of ~2.8 kbwas cloned and sequenced (JQ954859). Analysis of the sequence data
revealed 90-92% sequence identity with Papaya
leaf curl virus (PLCV) strains
(Fig. 3a) leading to identification of the isolate as a strain of
PLCV. The ~1.3 kb fragment obtained with the beta satellite specific primers was also cloned and
sequenced (JQ408217). This sequence
showed the highest identity (93%) and closest phylogenetic relationships
with Ageratum leaf curl beta C1 (AgLCB) strain (Fig. 3b). Several attempts to
detect a DNA-B genome by PCR using its specific primers (Padidam et al., 1995) or by restriction analyses of RCA products failed, which
indicates the begomovirus as monopartite. A literature search revealed that
Potato virus Y is the only reported virus infection so far in K.
indica (Wang et al., 2012). Thus,
the association of PLCV and a beta satellite with yellow vein disease of K. indica
is a new record. The disease is considered as significant, since aster
plants are grown in gardens for ornamental purposes and the infected ornamental
plants may serve as a virus reservoir for other hosts.